Brake



Marchz'l', 1945 R. A. GEPFRICH BRAKE Filed May 11, 1942 5 Sheets-Sheet 3 ATTORNEY March 27,' 1945. A R. A. GoEPFRlcH Y2,372,322

BRAKE Filed May 11, l1942 i 5 sheets-sheet 4 I March 2:7,l 1945. R, A, GOEPFRKSH BRAKE Filed May 11, 1942 'Sheets-Sheet 5 v INVENTOR EPFD/C/ Patented M0122?, 1945' Rudolph A. Gpfrieh, senin nena, 1nd., signor to Bendix Aviation Corporation, South Bend, Ind., a corporation of Delaware Appunti@ May 11, i942, serial No. 442,413

(ci. iss-106) 2 Claims.

. This invention relates to brakes, and is illustrated-as embodied in certain constructions of internal expanding drum brakes.

It is the chief object of my invention to furnish a brake which is at once extremely effective and easily controllable. To this end I utilize a vpair of shiftable anchorage friction devices each adapted to anchor at one end or the other and each having two parts or shoes pivotally connected together by an adjusting strut. Thus, within each shiftable friction device, one of the parts of the shoes always exerts a servo eii'ect on the other. f

s By using arcuate friction 'devices which are anchored and applied at their ends, but which are adjusted intermediate their ends to compensate for wear, I have simplified and overcome the adjustment problem. As brake friction devices wear they are usually adjusted by moving them radially toward the circumference of the drum. If the adjustment increases the distance between the friction devices and the actuators which .operate the friction devices, the adjusting is not accom` plishing its purpose. Where levers or other mechanical actuators are used to spread the friction devices (the levers -themselves may be operated hydraulically or mechanically). the adjustment must, in effect, change the length of the friction device. This I provide for by breaking the friction devices into two parts or shoes which have arc lengthening adjusting means between themA be eilected over a brake using varied sizes lutilizes four brake shoes.

o f a brake assembly showing a further modification of my invention;

Figures and 9 are figures taken on the lines l-l and 9 9 respectively of Figure 7? Figure l0 is a vertical section taken through a brake assembly on a plane just inside the head of a brake assembly showing a further modification of my invention; l

Figures 11 and l2 are figures taken pn the lines II--il and I2-I2,.respectively, of Figure 10;

Figure 13 is a vertical section taken through a brake assembly on a plane just4 inside the head Aof a brake assembly showing a further modification of my invention: and l Figure l4` is a section taken on the line Il-Id of Figure 13.

The several brake assemblies illustrated each These are preferably made identical in construction so that they may be produced ona large scale or mass production basis. Thus a considerable saving in cost may and designs of shoes.

Referring to the brake shown in Figures l to 4 inclusive, the assembly generally comprises four brake shoes II, I2, I3 and I4, a support or backing plate I5 on which the shoes are mounted, a

h rotatable brake drum I6, and anchoring and ap- A further object of my inventionis to applya lbrake of the type generally described above with a single control, as for example. a single hydraulic motor cylinder.

The above and other objects and advantages of the invention, including variousnovel combinations of parts and desirable Iparticular constructions, will be apparent from the following description of the illustrative embodiments shown in the accompanying drawings, in which:

- Figure 1 is a verticall section taken. through a brake assembly on a plane just inside the head ofabrake drum; j

Figures 2, 3 and 4 are ngures taken on the lines 2 2, 3 3, H, respectively. of Figure l:

Figure 5 is eil, vertical section taken through a brake assembly onza plane Just inside the head of a brake showing a modified form of my invention;

Flgure6 is a section taken on the of Pisure 5: c

Figure 7 is a vertical section taken through a brake assembly on a plane lust inside the head line 0 6.

plying means for the shoes. The shoes are divided into two pairs, the shoes of each pair being connected together by an adjusting strut, Il and I2 by a strut I'I, I3 and I4 by a strut I8. The struts I1 and I8 may each include a member I9 pivoted to and preventedv from rotation relative to one of the shoes in its pair and providing an interior threaded surface; an adjacent screw 2li having a stem screwed into the member I9 and a serrated head adapted to be turned for adjusting purposes.

vand a member 2l supporting the head o f screw 2l and 4pivoted to a-nd prevented from rotation relative to the other shoe in its pair. Springs 22 may/be connected between each pairof shoes to hold them against the adjusting strut and to prevent unwanted rotation ofthe serrated adjustnot of great consequence.

` difference in the tends to twkt the lever clockwise and direction Suchtwisting from the drum, 'the anchors 23 and 24 swing also swing the levers and simultaneously exert spreading force between the friction devices at both ends thereof andadjusting the anchors. Each lever applies force tothe shoes through its projections 32 and'33 each of which pivots on the web of one of the friction devices. A mechanical auxiliarybrake applying unit is provided comprising'a' tension member 3l and a lever 35 connected thereto and connected to or integral In the various modications, the changes are Most of the parts are closely similar to certain parts'already described in relation to the brake of Figures 1 to 4. Con sequently the similar 'not be in each case redescribed, but,'for purposes of clarity, the partsvof the modified brake shown in Figures 5 and 6 have been given parts in'Figures 1 to 4 IBB, the parts of the modilied brake shown in Figures 7 to 9 have been given the numerals of similar parts vin Figures 1 to 4 283, the parts of the modied brake shown in Figures 10 to 12 have been given the numerals of similar parts in Figures 1 to 4 30B, and the parts of the modified brake shown in Figures 13 and 14 have been given the numerals of similar parts inliiguresltoil".V

In the modification shown in Figures 5 and 6., the |23 and |29 apply force to the levers |33 and I3I through the intermediary of thrust links Ill and |42. Also there is some shape of 'the shoes and the the numerals oi' similarA applying force through the intermediate strut on y v the anchorlngshoe. Thus if the direction of ro- If the direction of the rotation of the drum is opposite that shown by the arrow, the friction device comprising shoes II and |.2 will anchor at 23 and the friction device comprising shoes I3 and I4 will anchor at 24. Eachof the friction devices is rotation, one of the shoes comprising the friction device anchors and the other shoe exerts an tation is that shown by the arrow, shoe l2 will act as a servo shoe in exerting an applying force through adjusting strut I on shoe II which will anchor at 24. Likewise shoe I4 will act as a servo shoe to exert applying force through adjusting strut I 8 on anchored shoe I3. If the direction of exceptional qualities applying levers, and in the-positioning of the springs |22. to 9 inclusive, 4the lever 235 is not directly' connected to the lever 23|. The lever 235 carries the 'projections.232 and 233, and the lever 23| has a projection 23|a which contacts the upper end of lever 2.35 to exert a spreading force on the friction devices through. the intermediary of the lever 235 and its projections. In the modification shown in Figures 10 to 12 inclusive, no hydraulic motor is used for applying purposes. but insteadthe levers 333 and 33| are actuated by a small equalized lever 35| which is connected at -352 to the lever 33| and is thrust link 353 'to the lever 333. vis arranged to be operated by a 33|. In the modicaticn of the tension member 333 exerts force on the levers 333 and 43| by means ot a direct connection with lever 43|, which in turnis connected bya thrust link 33| with lever 43|.

all of the modifications In the operation of l shown, s force applied at the end of the friction devicestion devices'gaimtthefbrake drum, and cach of the devices anchors at according to the direction of drum example, in Figure l, force applied tension member by the motor 3l in a coimterlever 3| in a clockwise of thelevers exerts an applying force at both ends of both friction devices through the intermediary of the projections Figures 13 and i4,

tends-to move both ot the frlc.

In the modication of Figures 7- fr one end or theother rotation.- Ror drum rotation is opposite that indicated by the b arrow, shoes I2 and I3 will'anchor, and shoes Il and I3 will act as their respective servo applying shoes.

It will be apparent from the y'above description that I have provided a brake which comprises the of effectiveness with ade quate controllability. The effectiveness is there because of the servo and self-energizing action of the various shoes. The controllability is present because I have used two individually shiftable friction devices which do not build up servo effect around the full cir erence of the brake drum and which, because they are'disconnected, do not occasionally have to one another;

Being aware of the possibilities of modiiications in theparticular structures herein described without departing from the fundamental principles of my invention, I do not intend that their scope be limited except as set forth by the appended claims.

l claim:

1. A brake comprising a rotatable brake drum,

a non-rotatable support, a pair of 4shi'ftable anchorage'friction devices each adapted to anchorat one end or the other according tothe direcltion of drum rotation at the time they contact the comprising a pair of floating applying levers each straddling one ofthe anchors and each acting on the ends of the ,friction devices adjacent thereto, a hydraulic motor mounted on the support near the center of one of the frictiondevices having pistons therein adapted to spread the ends of the levers to simultaneously exert a force at both ends of both friction devices tending to move them against the drum, Van 'extension `o i. one of said levers, anda cable connected actuate said lever mechanically. thereby moving one end of each friction device against the drum" while the other end of each friction device anchors at the opposite side of the brake, the lever' having the extension being moved away from the u hydraulic 2. A brake comprising a rotatable brake drum,

motor when the cable is actuated.

a nontable support, a pair of shiftable anchorage friction devices each Nhpted to anchor of itself a servo applying device, in the sense that, regardless of the direction of 'drum v to said extension tol at one end or the other acco ding to the direction of drum rotation at the time they contact the drum and each including two parts and anadjusting strut connecting the parts together to form an adjustable length two-wayservo device; a pair of anchors one at each side of the support between the friction devices, applying means comprising a pair of floating applying levers each acting on the adjacent ends of the friction devices at one side of the brake, a. hydraulic motor mounted on the support near the center of one of the friction devices having pistons therein adapted to spread the ends of the levers to simultaneously exert aforce at both ends lof both friction devices tending to move them against the drum, an extension on one of said levers, and a cable connected to said extension to a'ctuate said lever mechanically, thereby moving one end of each friction device against the drum while the other end of each friction device anchors at the opposite side of the brake, the lever having the extension being moved away from the hydraulic motor when the cable is actuated.

RUDOLPH A. GOEPFRICH. 

